<p>
  <mat-form-field appearance="outline">
    <mat-label>username</mat-label>
    <input matInput placeholder="username" [(ngModel)]="username" name="username">
  </mat-form-field>
</p>
<p>
  <mat-form-field appearance="outline">
    <mat-label>password</mat-label>
    <input matInput placeholder="password" type="password" [(ngModel)]="password" name="password" (keyup)="enter($event)">
  </mat-form-field>
</p>
<p>
  <button mat-raised-button color="primary" (click)="login()">登录</button>
</p>
